The who, what, where, when and how of China’s HD-981 oil rig foray into Vietnamese waters have been addressed comprehensively, both by commentators here at The Diplomat and elsewhere. The enduring question, as with many of China’s provocative actions in the Asia-Pacific, remains why? The opacity of China’s internal decision-making processes makes it rather difficult to conclusively answer that question, but a good amount of evidence suggests that the oil rig crisis with Vietnam was manufactured to test the mettle of ASEAN states and the United States. It gives Beijing an opportunity to gauge the international response to China asserting its maritime territorial claims.

As Carl Thayer points out on this blog and M. Taylor Fravel said in an interview with The New York Times, the China National Offshore Oil Company’s decision to move oil rig HD-981 was a premeditated move of territorial assertion. CNOOC may be a state-owned enterprise but the decision to move this $1 billion asset into an area with questionable hydrocarbon reserves while also inciting a diplomatic crisis speaks to the planned, political nature of this move. The fact that approximately 80 PLAN and Chinese coast guard ships accompanied the rig reinforces the notion that China was making a strategic push to assert its territorial claims in the region.

The decision to move oil rig HD-981 into disputed waters matches China’s decision to impose an air defense identification zone (ADIZ) over the East China Sea in terms of signaling China’s appetite to unilaterally pursue its maritime territorial claims. China has said that the oil rig will remain in these waters until August this year. What ultimately sets this episode apart from any other is that it is the first time China has placed an asset this expensive within the exclusive economic zone (EEZ) of another state. And Vietnam isn’t a pushover of a state either — it has a more-than-modest maritime capacity that could result in an armed altercation with China. Overall, in the past six months, we’ve seen China more assertive than ever in pursuing its claims and, for the moment, it is succeeding.